This isn't about dictatorship or the motivation for attack (and lets not forget that it was Britain and France that declared war on Germany, not the other way around. There is good evidence that Hitler neither wanted nor expected world war when he moved into Czechoslovakia and then Poland.)
The issue is the habitual disparagement of the French by some segments of US society. You're constantly throwing sand in the face of a country that should be a friend to you.
My point is that if the French are "retreat monkies" or whatever else they are being called, obviously people feel they would have done better in the same situation. Would the US have done better if crack German troops had smashed through Tennessee towards Washington in 1940?
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
